Check
2,
LCD
Displays
Anything?
1.
Turn
o
the
4338B .
2.
Turn
on
the
4338B
while
watching
the
LCD
.
3.
Check
for
a
beep
sound
for
a
moment
and
if
you
see
anything
is
displayed
on
the
LCD
.
4.
If
beep
sounds
and
LCD
displays
something,
proceed
to
\Check
3,
LCD
Operates
Correctly?",
otherwise
proceed
to
\Check
6,
CPU
P
ower
LED
Lights?".
Check
3,
LCD
Operates
Correctly?
1.
Turn
on
the
4338B .
2.
Reset
the
4338B.
3.
Check
if
the
LCD's
back
light
is
lit.
4.
Press
some
front
panel
keys
such
as
4
Meas
Prmtr
5
and
check
if
the
characters
are
correctly
displayed
in
the
whole
area
of
the
LCD
.
5.
If
the
LCD
operates
correctly
,
proceed
to
\Check
4,
Any
Error
Message
on
LCD?",
otherwise
replace
the
LCD
Assembly
.
Check
4,
Any
Error
Message
on
LCD?
1.
Turn
o
the
4338B .
2.
Turn
on
the
4338B
while
watching
the
LCD
.
3.
Check
if
the
LCD
displays
any
error
message
.
4.
If
an
error
has
NOT
occurred,
replace
the
A1
Main
Board
Assembly
,
otherwise
proceed
to
\Check
5,
CPU
Related
Error
Message?".
Check
5,
CPU
Related
Error
Message?
1.
If
the
error
message
is
one
of
the
following
replace
the
A2
CPU
Board
Assembly
,
otherwise
replace
the
A1
Main
Board
Assembly
.
a.
ROM
TEST
F
AILED
b.
RAM
TEST
F
AILED
c.
EEPROM
R/W
F
AILED
Note
When
replacing
the
A2
CPU
Board
Assembly
,
refer
to
\Replacing
the
A2
CPU
Board
Assembly"
in
Chapter
3
for
handling
the
ROM
and
EEPROM
on
the
A2
Assembly
.
Check
6,
CPU
P
ower
LED
Lights?
1.
Turn
on
the
4338B .
2.
Check
if
the
LED
\+5
V"
of
DS1
on
the
A2
CPU
Board
Assembly
lights
.
Refer
to
Figure
4-11
for
DS1
location.
3.
If
the
LED
lights
,
proceed
to
\Check
7,
Any
Error
Code
on
LED?",
otherwise
proceed
to
\Check
8,
CPU
Fuse
High
Lead
V
oltage
".
4-14
T
roubleshooting
